Strength, microstructure and durability of concretes cured by flue gas vacuum carbonation

烟气真空碳化养护混凝土的强度、微观结构和耐久性

• 批准号: RGPIN-2016-03625
• 负责人: Shao, Yixin
• 金额: $ 2.62万
• 依托单位: McGill University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=664874
• 关键词: Strength; microstructure; durability; concretes; cured

Early age carbonation curing of concrete is considered as one of the promising technologies for carbon capture and utilization in greenhouse gas mitigation exercise. Gaseous carbon dioxide is converted into solid calcium carbonates by calcium silicate carbonation and stored in concrete as nano crystals for performance enhancement. The process makes concrete greener, stronger and more durable. Currently the carbonation process works in a pressure chamber and with a carbon dioxide gas of 99% purity. Although it provides the best conditions for high degree of reaction, there are technical and economical challenges for large scale implementation. The first challenge is the use of pressure chamber. Most of the concrete producers do not use pressure chamber. To promote carbonation technology, it is imperative to develop a system that requires no pressure chamber. The second challenge is the price of the high purity gas. The commercial carbon dioxide gas costs about $500/ton. Unless it can be reduced to $50/ton, the gas price will remain an obstacle for applications. The question is if the as-captured flue gas can be used directly without chemical separation. This proposed research is directed to address the two challenges. A flue gas vacuum carbonation system will be developed to replace the pressure chamber and the pure gas in early carbonation process. The research will be carried out in four tasks: Task 1 is to establish a vacuum carbonation system with pure gas in a sealed-only chamber. It will serve the scenario when the recover CO2 is affordable. Task 2 is to develop a flue gas carbonation process in a pressure chamber to study the reaction efficiency with low concentration gas. Task 3 is to combine the techniques developed in Tasks 1 and 2 to examine the possibility of the flue gas carbonation in a vacuum system without pressure chamber. Task 4 will perform comprehensive microstructural and durability analysis of the concrete produced by early carbonation. Innovative carbonation devices will be designed and implemented to meet industry scale and the effectiveness of the technology will be assessed by strength gain and carbon uptake. Two typical concrete products will be used to test the developed process. They are concrete paving stones as precast product and concrete slabs such as pavements or bridge decks as cast-in-place product. Both products serve in severe outdoor exposure conditions and will benefit from carbonate precipitation for durability improvement. If successful, early carbonation curing can find more applications in both precast and cast-in-place concretes for carbon storage and performance enhancement at an affordable price. The developed technology will become the "game changer" in the construction industry.

混凝土早龄期碳化养护被认为是温室气体减排中碳捕获和利用的一项有前景的技术。通过硅酸钙碳酸化将气态二氧化碳转化为固体碳酸钙，并以纳米晶体的形式储存在混凝土中以增强性能。这个过程使混凝土更环保，更坚固，更耐用。 目前，碳酸化过程在压力室中进行，二氧化碳气体的纯度为99%。虽然它为高反应度提供了最佳条件，但大规模实施存在技术和经济挑战。第一个挑战是压力室的使用。大多数混凝土生产商不使用压力室。为了推广碳酸化技术，开发一种不需要压力室的系统势在必行。第二个挑战是高纯度气体的价格。商业二氧化碳气体的成本约为500美元/吨。除非能降至50美元/吨，否则天然气价格仍将是申请的障碍。问题是捕获的烟气是否可以直接使用而无需化学分离。这项研究旨在解决这两个挑战。将开发烟气真空碳酸化系统来替代早期碳酸化过程中的压力室和纯气体。本研究将分四个任务进行：任务1是建立一个纯气体的真空碳酸化系统在一个密封的唯一室。它将服务于当回收CO2是负担得起的情况。任务二是在压力室中开发烟气碳酸化过程，以研究低浓度气体的反应效率。任务3是将任务1和任务2中开发的技术联合收割机结合起来，以检查在没有压力室的真空系统中烟气碳酸化的可能性。任务4将对早期碳化产生的混凝土进行全面的微观结构和耐久性分析。创新的碳化设备将被设计和实施，以满足工业规模，该技术的有效性将通过强度增益和碳吸收来评估。两个典型的混凝土产品将被用来测试开发的过程。它们是作为预制产品的混凝土铺路石和作为现浇产品的混凝土板，例如人行道或桥面。这两种产品都适用于恶劣的户外暴露条件，并将受益于碳酸盐沉淀，以提高耐久性。如果成功的话，早期碳化固化可以在预制和现浇混凝土中找到更多的应用，以合理的价格进行碳储存和性能增强。开发的技术将成为建筑行业的“游戏规则改变者”。